Tension scarf for timbers



UNITED STATES i raiE Nfi'ff` orifices.

WILLIAM T. DoNNELL'oF BROOKLYN, NEW Yoan.

TENSION scARrroa fr.1i/rimas,j.`

To @ZZ whom z't 71mg/ concern .f Y'

Be it known that 'VILLIAM T. DoNf NELLY, av citizen of thelUnite'd States, and a and other structures employing` large and long timbers which are usually exceedingly difficult to provide. It has for its object tok provide a fabricated timber scarfing for joining theends of lumber, whereby said lumber will be `more .efficiently utilized, and the largest possible percentage of'strength thereof secured at thejoint portion.

A further object ofthe invention consistsV in the provision for increasing the tensilestrength of the splice through the compression of the timber ends. The nature of the invention will be best understood when described in connection with the accompanying drawings in which- Y Y F ig. lis a detached view, illustrating the ends of two pieces of timber shaped in accordance withthe invention.

vFig.2 is a sideelevation of two. beams united in accordance with the present invention; and Fig. 3 is, a plan thereof.

Similarcharacters of 'reference designate corresponding parts throughout the several views.v Y Referring to the drawings, 10 and 11 designate `two timbers .which it is desired toV unite, and .whose ends are formed in manner hereinafter set forth, substantially as shown in Fig. l of the drawings, the two vends being duplicates ofeach other butapplied in reverse direction, as indicated. To provide the increased jtensile strength,as wellv as strength. against lateral stress, the ends of each length vof timber to be united' are provided with a plurality of'tongues, for

' example 12 and 13, and 12" and 13', as indi-v .the outer side of tongue 13 is also cut away Vcated in Fig.V 1.1 The twotongues enclose an" inwardly tapering cutaway-portion 14, and' to provide a space 15 with which the tongue 13 of the oppositely-directed timber 11l 1s designed to register, the tongues 12 and 13 registering` with the spacesV 14 and 15 of the timber 10, the` tongues .of a set being upon Application' med August 31,1915. i seiiaiNo. $252,145. Y

f Specication of Letters Patent. i 'atnted pl.

opposite sides of vthe median plane` ofthe timber. Conversely, thetongues 12and 13 regis-ter with the spaces 14'k and lofniemberfllf. Thefs'anie forma snugfiit between 'theendsl and'arcfof vincreasing taperi'nwardly; and by multiplying same as' herein indicated, the frictional holdingl properties of the joint are correspondingly increased.'

. In order to secure anV increased tensile strength of the joint portion, there is placed a compression upon the interlocking` ends of the timbers 10 andll, in that each'is provided with a saw-cut 16 and 16 respectively,

extending backwardlyinto the timbers from' vthe inner end ofthe spaces 14 and 14', the

slotting being effected immediately along one wall of the central scarf or median planeofL the beam and beyond the extent of the scarfing. Bolts 20, which are preferably ofthe drive screw bolt type, as more fully set` forth in U, S. Patent No. 1273588, granted me'the 23rd day of July, 1918, are caused to extend through the various tongues, as well asthrough outer reenforcing planks 21 and 22 when these are employed, the saine thenezgtending over thel joint and a certain distance.

beyond. These planks serve to maintain the Veffective section of thetimbers, but may be dispensed `with in somev instances. It is to be noted, moreover, in connection wlth the use of the bolts 20, that by virtueof the multiplicities of splicings, the resistanceto shear vstance shown, threetiines greater than when employedk in connection with a splice of the usual form. In addition, the length ofthe joint is reduced thereby, permitting of the --of said fastening membersy is greatly in- Y creased, in fact being,.in the particularv int-190 grip the endsof the splice.;4 Additional drive or f :ompression bolts, are Vemployed beyond ,the extentof the joint in order to gain full advantage of 4the, compression, and aV few` spikes `23may be driven into the timbersto further help to retain the planks thereto. It

iszto be noted, also, 'thatthe fastening meinl` bers extending through the Splice portion are in triple shear, as a result of doubling of the scarng, although a' further multiplyingpof tionate increase of the shear.

`Iclaim:` y j j `1. A tension scarf for thecoacting'f ends of twoV timbershaving'their abutting ends the scarng would not maintain the proportween the tongues.

A tension scztri3 for the coacting ends of two timbers having their abutting ends provided ivith a plurality of similar tongues, said abutting ends being in reverse position With their tongues interlocking, and provided at the innermost portion of the scarf with inwardly directed saw-outs extending from the space between the tongues, and bolts passing through both of the tongues and the joint thusformed,

Signed at New York, in the county of j New York and @tate of New York, this 29th dey of August, A. D. 1918.

WILLIAM T. DONNELLY. i 

